If the selector lever will not move from P using the proper shift procedure, continue to hold down the brake pedal.

Take the vehicle to an Authorized Mazda Dealer to have the system checked.
Shift-Lock System
Manual Shift ModeTiming Chain Removal/Installation [Skyactiv G 2.0]
WARNING:
A hot engine can cause severe burns. Turn off the engine and wait until it
is cool before servicing.
CAUTION:
If the camshaft is rotated with the timing chain removed and the piston at
the top dead center position, the valve may contact the piston and the engine ...
Front Brake (Disc) Inspection
Brake Judder Repair Hints
Description
1. Brake judder concern has the following 3 characteristics:
Steering wheel vibration
1. The steering wheel vibrates in the rotation direction. This characteristic
is most noticeable when applying brakes at a vehicle speed of 100—140 km/h {62.2—86.9
...
Clutch Cover Inspection [C66 M R]
1. Remove the clutch cover..
2. Perform the following procedures to inspect the clutch cover.
If it exceeds the maximum specification, replace the clutch cover..
a. Measure the wear of the diaphragm spring fingers.
Clutch cover diaphragm spring fingers maximum depth
0.6 ...